Attachments to crutches



Nov. 3, 1942. 'p F. DOUGLAS-- ATTACHMENTS TO CRUTCHES Filed Sept. 20,1941 Patented Nov. 3, 1942 Philip FaircleughDougla s, Carman, Manitoba,

Canad Application 3 Claims.

My invention relates to attachments to crutches, a principal object ofthe invention being to provide arrangements of the character herewithindescribed, by the use of which considerably greater comfort may bederived by the user, together with a substantial reduction in the shockcaused each time the crutches strike the ground.

A further object of my invention is to provide in crutches, arrangementsby the use of which greater speed of locomotion becomes possible, or inother words, longer strides with the use of crutches tted with myhereinafter described arrangement.

A further object of my invention is to provide a ferrule attachment,which is economical to manufacture, easy to attach and which will notbecome out of order as and for the above purpose.

With the above more important objects in View and such other minorobjects as may appear as the specification proceeds, my inventionconsists essentially in the arrangement and construction of parts all ashereinafter more particularly described, reference being had to theaccompanying drawing, in which:

Figure 1 is a sectional side elevation of my invention, showing the samein situ on the crutch.

Figure 2 is a modified form of my invention using a different type of aplunger.

In the drawing like characters of reference indicate corresponding partsin the different figures.

It is well known that considerable discomfort is experienced by crippleswho are obliged to resort to the use of the crutches, through theunyielding construction thereof and that the speed, freedom of movementand safety of such persons are greatly hampered by expectations of ashock which is transmitted to their body every time a step with thecrutches is taken.

My arrangements herewithin described and illustrated in the accompanyingdrawing are therefore designed to overcome the above objections, andreferring lrst to my ferrule attachment I shown in Figure 1, this willclearly be seen as attached to the crutch 2 below the junction of theforked end y3. In this context I would remark that generally speaking,it will be found necessary to cut oi a portion of this end of the crutchbelow the junction of the forks.

My attachment I comprises a hollow openended and tapered sheath 4secured to the forked shank by means of the bolts 5. The elongatedaperture 6 at the lower end of the sheath is internally screw-threadedas at 'I to receive the upper, externally screw-threaded shank of aplunger 8.

september 2o, 1941, serial No. 411,752

In Canada September 19, -1940 (Cl. 13S-50) diameteras at 9, designed fora free sliding fit.

within a ferrule I0, and is provided'with an axial, cylindrical cavityII. A pair of compression springs I2 and I3 of different resilienciesare positioned in this cavity and extend between the plunger 9 and thelower wall I4 of the ferrule.

The two dilerent diameters of the plunger 8 provide an annular shoulderI5 designed to engage the lower annular perimeter of a boss I6 whenthesprings I2 and I3 are in relaxed position. lThe boss is provided atthe upper end thereof with an outwardly projecting annular flange Il,below which it is externally screwthreaded, as at I8, to engage theinternally screwthreaded upper end I9 of the ferrule III.

Referring now to the accompanying Figure 2, a modified arrangement of myinvention will be seen, in which the plunger 8 is provided with acylindrical portion 2i) of an enlarged diameter, the piston surface 2Iof which bears against the inside wall of the ferrule I0.

The lower end 22 of the plunger is of a reduced diameter and extendsinto a coil spring 23, which in turn is positioned within the cavity IIof the ferrule I0. In all other respects this embodiment is similar tothat shown in Figure 1, including the provision of a conventional rubberferrule 24 as will clearly be apparent from the drawing.

From the foregoing will be seen that when the weight of the user isexerting a downward pressure upon the crutch, the springs I2 and I3 willbecome compressed, so that in the action of walking with crutches ttedwith my ferrule attachment, the tendency of the springs to relax willgreatly assist the user in his motion.

I also Wish to point out that any possibility of wobble in my ferruleattachment is eliminated by the piston surface 2l which being ofsubstantial length and in engagement with the inner wall of the ferruleIII prevents any side play of the plunger 8.

Since various modifications can be made in my invention as hereinabovedescribed and as illustrated in the accompanying drawing, and manyapparently widely different embodiments of same made within the scope ofthek claims Without departing from such spirit and scope, it is intendedthat all matter contained in the accompanying specification and drawingshall be interpreted as illustrative only and not in a limiting senseand I desire only such limitations placed thereon as are specificallyexpressed in the accompanying claims.

ed upper end What I claim as my invention is:

1. Attachments to crutches comprising in combination, a hollow taperedsheath designed to encase the lower forked ends of crutches, the lowerend of said sheath being apertured and internally screw-threaded, aplunger externally screw-threaded at the upper end thereof to engage theinternally screw-threaded portion of said sheath, a ferrule, a coilspring therewithin, the upper end of said ferrule being internallyscrew-threaded, an externally screw-threaded boss engageable with theinternally screw-threadof said ferrule, an external annular fiangeadjacent the upper end of said boss and engageable with the upperperimeter of said ferrule, said plunger extending through said boss intosaid ferrule, the lower end of said plunger having an axial, cylindricalcavity formed therein to receive the upper end of said spring.

2. The device as deined in claim 1 in which ,the lower end of saidplunger is in irictional engagement with the inside wall of saidferrule.

vboss engageable with the internally screw-threaded upper end of saidferrule, an external annular iiange adjacent the upper end of said bossand engageable with the upper perimeter of said ferrule, said plungerextending into said ferrule through said boss, a cylindrical blockformed intermedially the length of said plunger and in frictionalengagement with the inside wall of said ferrule, the lower end of saidplunger extending into the upper end of said spring.

PHILIP F. DOUGLAS.

